We will develop three promising cost-effective self-help approaches to smoking cessation and evaluate them in a large randomized controlled trial among enrollees of Group Health Cooperative of Puget Sound, the fourth largest HMO in the U.S. The results will establish the value of a comprehensive mailed quitting guide and assess whether minimal therapist contact and bolstered natural social supports for quitting influence results of a written self-help guide. Multidimensional assessment will clarify how these self-help approaches affect the methods, motivations, and expectations of self-quitters and alter long-term changes in their smoking behavior. Prospective subjects will be recruited through Group Health's monthly magazine and referrals by Group Health physicians and nurses. Those meeting inclusion criteria will receive a motivational letter, quit smoking pamphlet, bibliography of self-help manuals, baseline questionnaire, and consent form. Subjects recruited will then be randomly assigned to one of the following groups: (1) the American Lung Association manual "A Lifetime of Freedom from Smoking" plus a new quitting procedure incorporating nicotine fading techniques; (2) the material in (1) plus information sent to subject-identified supportive individuals on how to provide more effective support to the prospective quitter; (3) the material in (2) plus four telephone calls from a counselor; and (4) nothing beyond the initial letter, pamphlet, and bibliography. All materials will be sent through the mail. Follow-up of quit rates and experiences will be carried out by mailed questionnaires with telephone follow-up at 6, 12, 24, and 36 months. Salivary continine will be measured for all self-reported quitters at 36 months. Program effectiveness and factors important in the quitting process will be analyzed in relation to sex, age, source of referral, and smoking history. Our study will provide a rigorous, long-term evaluation of three inexpensive, replicable self-help quit smoking approaches.